Chemistry 1A - Foothill College
Chapter 1: Matter and Measurement
The topics in this chapter should be
review from a previous course. It is
expected that you are able to review
and master this material quickly and
somewhat independently.
From this Chapter you should:
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Understand the basics of the Scientific Method.
Recognize elements, atoms, compounds and molecules.
Be able to identify physical and chemical properties and changes.
Be able to apply the kinetic molecular theory to the properties of
matter.
• Develop proficiency with metric units and dimensional analysis.
• Be able to use significant figures properly, understanding how they
relate to uncertainty in measurements. (Covered in LAB.)
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The Scientific Method
The scientific method provides guidelines for the practice of
science.
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Collect data (observe, experiment, etc.).
Look for patterns.
Try to explain data; develop a hypothesis or tentative explanation.
Test hypothesis, then refine it.
Bring information together into a scientific law, a concise statement
or mathematical equation that summarizes or describes the behavior
of matter.
Bring hypotheses and laws together into a theory. A theory should
explain general principles. A theory must have considerable
evidence or facts to support it.
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Matter
Solutions are
Homogeneous mixtures
Classifying Matter
Matter
Occupies Space
Heterogeneous Matter
Not uniform throughout
Homogeneous Matter
Uniform throughout
Solutions
Uniform but variable composition
Sand and dirt
is a
heterogeneous
mixture
Pure Substance
Fixed composition
Cannot be further purified
Elements
Cannot be divided into simpler substances
Compounds
Elements united in fixed ratios
Ionic
(salts)
Covalent
(molecules)
Molecules of
antifreeze
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Elements and Compounds
• Elements combine
chemically to form
compounds.
• Compounds can be
either ionic (saltscations and anions) or
covalent (molecules).
• Law of Constant
Composition (Definite
Proportions):
NaCl (ionic) is formed chemically from sodium and chlorine in a
oxidation-reduction reaction; the result is a solid that contains
oppositely charged ions arrange in an extended three dimensional
pattern called a lattice.
Covalent:
discrete molecules
held together in
specific shapes
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Properties of Matter
Each pure substance has a unique set of physical and chemical
properties that can be used to identify it. Are the following properties
physical or chemical?
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Intensive vs. Extensive Properties
• Extensive properties depend upon the amount of
substance present.
– Examples?
• Intensive properties do not depend upon the amount of
substance present.
– Examples?
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Physical and Chemical Changes
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In physical changes
the identity of the
substance is
preserved (no
chemistry).
Examples?
Physical
change Napthalene melts.
In chemical changes a
new substance(s) is
produced (chemistry).
Examples?
Chemical
change - Formation
of water from its
elements.
Physical changes
often occur with
chemical changes.
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Kinetic Molecular Theory
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Matter consists of small particles; atoms, molecules or ions that are in
constant, random motion.
As temperature increases, the average kinetic energy of the particles
increases and the motion becomes more rapid.
HEAT FLOW:
Matter has three physical states. Physical state depends upon the
nature of the substance (its identity), its temperature and the pressure
exerted upon the substance. As chemists we describe these states at
either the macroscopic level or microscopic (particulate) level.
Conversion between these states is a physical process.
Solid
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Liquid-solid
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Temperature
• Temperature is a
measure of average
kinetic energy of
the particles within
matter.
• We will use the
Kelvin (K) and
Celsius scales (°C).
• Be able to convert
between them:
K = °C + 273.15
°C = K - 273.15°
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Kinetic Molecular Theory and Physical State
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Units of Measurement
• Be able to
recognize the SI
units.
• Memorize the
common metric
prefixes!
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Derived Units of Measurement
Formed using the SI base units. For example, velocity is distance
traveled per unit time, thus m/s.
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Volume
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Derived Units of Measurement
Formed using the SI base units.
• Density
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Unit ConversionsDimensional Analysis
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English - Metric
Metric - Metric
Ratios
Sequential
Converting squared and cubed units
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Uncertainty and Errors in
Measurements:
• Accuracy
• Precision
• Significant Figures (Lab Exercise)
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Questions and Problems
Text Problem 1.62: Give the derived SI units for each of the
following quantities in base SI units:
a) acceleration = distance/time2
b) force = mass × acceleration
c) work = force × distance
d) pressure = force/area
e) power = work/time.
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Questions and Problems
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List the basic differences between mixtures and compounds:
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Text Problem 1.1: Which of the following figures represents (a) a
pure element, (b) a mixture of two elements, (c) a pure compound,
(d) a mixture of an element and a compound? (More than one picture
might fit each description.)
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Questions and Problems
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Text Problem 1.58: A sample of ascorbic acid (vitamin C) is
synthesized in the laboratory. It contains 1.50 g of carbon and 2.00 g
of oxygen. Another sample of ascorbic acid isolated from citrus fruits
contains 6.35 g of carbon. How many grams of oxygen does it
contain?
Which scientific law are you assuming in answering this question?
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Text Problem 1.68: Small spheres of equal mass are made of lead
(density = 11.3 g/cm3), silver (10.5 g/cm3), and aluminum (2.70
g/cm3). Which sphere has the largest diameter, and which has the
smallest?
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Questions and Problems
• Convert 4.773 yd3 to cm3.
• If an automobile is able to travel 254 mi on 11.2 gal of gasoline, what
is the gas mileage in km/L?
• A pound of coffee beans yields 50 cups of coffee (4 cups = 1 qt). How
many milliliters of coffee can be obtained from 1.0 g of coffee beans?
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Questions and Problems
• Text Problem 1.31: Gold can be hammered into extremely thin
sheets called gold leaf. If a 200-mg piece of gold (density = 19.32
g/cm3) is hammered into a sheet measuring 2.4 × 1.0 ft, what is the
average thickness of the sheet in meters?
How might the thickness be expressed without exponential notation,
using an appropriate metric prefix?
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Questions and Problems
• The anesthetic procaine hydrochloride is used during dental
surgery. It is packaged as a 10.0% solution by mass in
water. The density of the solution is 1.1 g/mL. If a dentist
injects 0.50 mL of the solution into a patient, what mass of
procaine hydrochloride is injected?
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